Downsampling a PSD that was generated by zero-padding - worth it?

1. What is the effect of zero padding?
2. Why is it necessary to pad an image with zeros before computing its DFT?
3. Does zero padding reduce spectral leakage?
4. What is zero padding Why is it needed?

What is the effect of zero padding?

Zero padding enables you to obtain more accurate amplitude estimates of resolvable signal components. On the other hand, zero padding does not improve the spectral (frequency) resolution of the DFT. The resolution is determined by the number of samples and the sample rate.

Why is it necessary to pad an image with zeros before computing its DFT?

If one has any interest in the spectrum of the windowing function used to isolate the time-domain sample, then zero-padding WILL increase the frequency resolution of the windowing function.

Does zero padding reduce spectral leakage?

Zero-padding a signal does not reveal more information about the spectrum, but it only interpolates between the frequency bins that would occur when no zero-padding is applied. In particular, zero-padding does not increase the spectral resolution.

What is zero padding Why is it needed?

Zero padding is a technique typically employed to make the size of the input sequence equal to a power of two. In zero padding, you add zeros to the end of the input sequence so that the total number of samples is equal to the next higher power of two.